r4674 - developers/werner/wlan-spi/patches

[werner at docs.openmoko.org]

Author: werner
Date: 2008-09-27 16:37:38 +0200 (Sat, 27 Sep 2008)
New Revision: 4674

Modified:
   developers/werner/wlan-spi/patches/hack-silence-battery.patch
   developers/werner/wlan-spi/patches/tweak-spi.patch
Log:
- moved SPI clock setting from hack-silence-battery.patch (oops !) to 
  tweak-spi.patch
- set the maximum SPI clock to 12MHz and explained what happens if we exceed
  this limit
- removed unnecessary dummy read before last SPI byte



Modified: developers/werner/wlan-spi/patches/hack-silence-battery.patch
===================================================================
--- developers/werner/wlan-spi/patches/hack-silence-battery.patch	2008-09-27 00:49:01 UTC (rev 4673)
+++ developers/werner/wlan-spi/patches/hack-silence-battery.patch	2008-09-27 14:37:38 UTC (rev 4674)
@@ -14,16 +14,3 @@
  		return ret;
  	}
  
-Index: korig/arch/arm/mach-s3c2440/mach-gta02.c
-===================================================================
---- korig.orig/arch/arm/mach-s3c2440/mach-gta02.c	2008-09-26 21:19:03.000000000 -0300
-+++ korig/arch/arm/mach-s3c2440/mach-gta02.c	2008-09-26 21:19:07.000000000 -0300
-@@ -1239,7 +1239,7 @@
- static struct spi_board_info gta02_spi_mmc_bdinfo = {
- 	.modalias	= "mmc_spi",
- 	.irq		= IRQ_EINT3,	/* unused ? */
--	.max_speed_hz	= 25 * 1000 * 1000,
-+	.max_speed_hz	= 10 * 1000 * 1000,
- 	.bus_num	= 0,
- 	.chip_select	= 0,
- 	.mode		= SPI_MODE_0,

Modified: developers/werner/wlan-spi/patches/tweak-spi.patch
===================================================================
--- developers/werner/wlan-spi/patches/tweak-spi.patch	2008-09-27 00:49:01 UTC (rev 4673)
+++ developers/werner/wlan-spi/patches/tweak-spi.patch	2008-09-27 14:37:38 UTC (rev 4674)
@@ -1,18 +1,23 @@
-Work in progress. Makes spi_s3c24xx.c work for 1 and 10MHz.
-Something breaks at 20 or 25MHz.
+Work in progress. Makes spi_s3c24xx.c work for up to 12MHz.
 
+At speeds of 13MHz or higher, we have setup time issues. I.e., the
+SPI host sees the data coming from the device delayed by one bit,
+even though things look fine on the scope.
+
+This 12MHz/13MHz "barrier" exists with or without probes attached,
+suggesting capacitative loading plays only a minor role in this.
+
 Index: korig/drivers/spi/spi_s3c24xx.c
 ===================================================================
---- korig.orig/drivers/spi/spi_s3c24xx.c	2008-09-26 20:47:30.000000000 -0300
-+++ korig/drivers/spi/spi_s3c24xx.c	2008-09-26 21:06:23.000000000 -0300
-@@ -198,6 +198,29 @@
+--- korig.orig/drivers/spi/spi_s3c24xx.c	2008-09-27 11:28:42.000000000 -0300
++++ korig/drivers/spi/spi_s3c24xx.c	2008-09-27 11:29:40.000000000 -0300
+@@ -198,6 +198,27 @@
  	writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
  	wait_for_completion(&hw->done);
  
 +	/*
 +	 * Get the last byte. Since we don't have more data we can send in
-+	 * order to clock the byte out of the SPI system, we need to wait and
-+	 * to provide a clock by a dummy read.
++	 * order to clock the byte out of the SPI system, we need to wait.
 +	 *
 +	 * Duh, I'm just handwaving here about possible explanations of what's
 +	 * going on in the hardware. This is the voodoo ritual that makes it
@@ -20,7 +25,6 @@
 +	 */
 +	if (hw->rx && hw->count) {
 +		udelay(1+10*1000000/spi->max_speed_hz);
-+		//readb(hw->regs + S3C2410_SPRDAT);
 +		hw->rx[hw->count-1] = readb(hw->regs + S3C2410_SPRDAT);
 +	}
 +
@@ -35,7 +39,7 @@
  	return hw->count;
  }
  
-@@ -233,8 +256,23 @@
+@@ -233,8 +254,23 @@
  
  	hw->count++;
  
@@ -61,3 +65,16 @@
  
  	count++;
  
+Index: korig/arch/arm/mach-s3c2440/mach-gta02.c
+===================================================================
+--- korig.orig/arch/arm/mach-s3c2440/mach-gta02.c	2008-09-27 11:29:48.000000000 -0300
++++ korig/arch/arm/mach-s3c2440/mach-gta02.c	2008-09-27 11:30:13.000000000 -0300
+@@ -1239,7 +1239,7 @@
+ static struct spi_board_info gta02_spi_mmc_bdinfo = {
+ 	.modalias	= "mmc_spi",
+ 	.irq		= IRQ_EINT3,	/* unused ? */
+-	.max_speed_hz	= 25 * 1000 * 1000,
++	.max_speed_hz	= 12 * 1000 * 1000, /* SPI doesn't want to go faster */
+ 	.bus_num	= 0,
+ 	.chip_select	= 0,
+ 	.mode		= SPI_MODE_0,